| Discovery [1] | |
|---|---|
| Discovered by | Harvard College Obs. |
| Discovery site | Oak Ridge Obs. (Agassiz Stn.) |
| Discovery date | 1 August 1981 |
| Designations | |
| (3401) Vanphilos | |
Named after | Vanessa Hall Philip Osborne (friends of G. V. Williams)[2] |
| 1981 PA · 1946 DA | |
| Mars crosser [1][3][4] | |
| Orbital characteristics [1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 70.38 yr (25,708 days) |
| Aphelion | 3.2195AU |
| Perihelion | 1.5147 AU |
| 2.3671 AU | |
| Eccentricity | 0.3601 |
| 3.64yr (1,330 days) | |
| 264.28° | |
| 0° 16m 14.16s / day | |
| Inclination | 21.797° |
| 322.38° | |
| 108.64° | |
| Mars MOID | 0.1190 AU |
| Physical characteristics | |
| Dimensions | 7.023±1.045 km[5] 7.10±4.56 km[6] 10.30 km(calculated)[4] |
| 4.225±0.001 h[7] 4.226±0.001 h[8] 4.2261±0.0005h[a] 4.227±0.005 h[9] | |
| 0.20(assumed)[4] 0.31±0.15[6] 0.377±0.198[5] | |
| SMASS =S [1] · S [4] | |
| 12.29±0.27[10] · 12.3[1][4][5] · 12.65[6] | |
3401 Vanphilos, provisional designation1981 PA, is a stony, eccentricasteroid and sizeableMars-crosser, approximately 7 kilometers in diameter. It was discovered on 1 August 1981, by and atHarvard'sOak Ridge Observatory (Agassiz Station) in Massachusetts, United States.[3]
Vanphilos orbits the Sun in theinner main-belt at a distance of 1.5–3.2 AU once every 3 years and 8 months (1,330 days). Its orbit has aneccentricity of 0.36 and aninclination of 22° with respect to theecliptic.[1] In 1946, it was first identified as1946 DA at the FinnishTurku Observatory, extending the body'sobservation arc by 35 years prior to its official discovery at Harvard.[3]
In theSMASS taxonomy, Vanphilos is characterized as a commonS-type asteroid.[1]
In February and March 2008, three rotationallightcurves of Vanphilos were obtained from photometric observations by astronomersPetr Pravec, James W. Brinsfield andRobert Stephens. Light-curve analysis gave a well definedrotation period of 4.225 and 4.226 hours, respectively, with a change in brightness between 0.50 and 0.54magnitude (U=3/3/3).[7][8][a]
In August 2014, astronomerBrian Warner derived a concurring period of 4.227 hours with an amplitude of 0.62 magnitude from his observations taken at the Palmer Divide Station in Colorado (U=3).[9] Light-curve plots were published on-line by theOndřejov Observatory and the Center for Solar System Studies.[b][c]
According to the survey carried out by NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission, Vanphilos measures 7.02 and 7.10 kilometers in diameter, and its surface has analbedo of 0.377 and 0.31, respectively.[5][6] TheCollaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 10.30 kilometers, as the lower the body's albedo (reflectivity), the larger its diameter, at a constant absolute magnitude.[4]
Thisminor planet was named for Vanessa Hall and Philip Osborne, by astronomer G. V. William to celebrate their marriage on 3 August 1991.[2] The approved naming citation was published by theMinor Planet Center on 25 August 1991 (M.P.C. 18644).[11]
